Add non-free warning to integration manager

https://github.com/SchildiChat/SchildiChat-android/issues/130#issuecomment-1657198941

Change-Id: I0f5af145697f14b2e6e83095993fdb158b41b3d8

library/ui-strings/src/main/res/values/strings_sc.xml

@@ -237,4 +237,6 @@
     <string name="settings_call_ringtone_use_default_stun_summary">Will use %s as assist when your homeserver does not offer one (your IP address will be seen by the stun server during a call
 )</string>
 
+    <string name="settings_integrations_scalar_warning">⚠️ This setting by default (unless overridden by your homeserver\'s configuration) enables access to \"scalar\", Element\'s integration manager which is unfortunately proprietary, i.e. its source code is not open and can not be checked by the public or the SchildiChat developers.</string>
+
 </resources>

vector/src/main/res/xml/vector_settings_general.xml

@@ -64,6 +64,11 @@
             android:persistent="false"
             android:summary="@string/settings_integrations_summary" />
 
+        <im.vector.app.core.preference.VectorPreference
+            android:focusable="false"
+            android:persistent="false"
+            android:summary="@string/settings_integrations_scalar_warning" />
+
         <im.vector.app.core.preference.VectorSwitchPreference
             android:key="SETTINGS_ALLOW_INTEGRATIONS_KEY"
             android:persistent="false"